Aerodynamic member



Aug. 21, 1945. ZAP Y 2,383,102

AERODYNAMIC MEMBER v Filed Feb. 13, 1942 2 Shee ts-Shee; 1

EDWARD F. ZA Br HA RR/J, K/ECA; FosrsR & HA RR/s A TOQNEKS Aug. 21, 1945. E, F. ZAP 2,383,102

AERODYNAMIC MEMBER Filed Feb. 13, 1942 2Sheets-Sheet 2 INVENTORI EDWARD f-TZAP y HARRIS) K1504 P057251? as HARRAS ATTOI yA-IKS Patented Aug. 21, 1945 UNITED STATES PATENT -OFFICE Amonrmmc MEMBER Edward F. Zap, Los Angeles: Calif. Application February 13, 1942, Serial No. 436,131

-: Clair us, (01.244-90) My invention relates to aerodynamic members such as flaps, ailerons, and the like for control-i ling aircraft in flight and is particularly directed to improvements in an aerodynamic member of the type that is retractably extended into .the air stream. f

Forthe purpose of the present disclosure the invention will be described as embodied in an aileron mounted on the wing of an airplane, but it will be readily understood that the same principles may be incorporated in other. types of telescoping aerodynamic members mounted on other parts of an airplane.

The particular aileron chosen to exemplify the invention is mounted in a hollow portion of the airplane wing to move outward from a retracted position at which it istelescoped into the wins, the outward movement being, for example, upward to extended position at which it is acted upon by the air stream. The aileron moves through an opening on the upper side of the wing.-

and the wing has additional openings on the lower side to permit air to flow upward through the wing when the aileron is extended. In some practices the lower openings may be omitted.

Lateral or rolling control of the aircraft by such an aileron arrangement is achieved both by spoiling lift in the wing and by additionally set ting up positive downward reaction of the wing to the air stream. At high speeds of flight the aileron is usually only slightly extended for a control effect and functions primarily as a deflection obstacle in the air, the eddies resulting from the obstacle both serving to spoil thewing lift and to increase drag while simultaneously the reaction of the wing-to deflection of the air stream results in a desirable downward thrust on ment as well as a favorable yaw. At lower speeds the aileron is extended further upward from the wing, but the dominant factor in control may be the flow of air upward through the wing, rather than the aerodynamic effect of the elevated aileron.

An important consideration in designing ailer-w ons of the described character is the effect of aerodynamic forces on the aileron with respect to movement of the aileron along its path of extension and retraction. In prior art arrangements of the general type. in mind here, the one pressing problem is to avoid an excessive tendency on the part of the aileron to retract as a result of pressure from the air stream. More often than not this problem is only partially met and excessive forces are imposed on the mechanism controlling the aileron. In my copending application, Serial No. 383,570, entitled Control system forairplanes," I teach an effective solu-' tion for this problem that consists in giving the aileron panel a curved configuration and in pro.- viding means for the aileron to move upward and outward in a curved path, the two centers or axes of curvature being outside and above the wing.

My prior application reveals that a simple curved panel mounted for movement along such a curved path will tend to move outward in response to the air stream if the center or centers of curvature of the panel are forward of the center or centers of curvature of the path; will tend to move inward in response to the air stream if the center or centers of curvature of the panel are rearward of the center or centers of curvature of the path; and will be neutral or non-responsive to the air streainif the center or centers of curvature of the panel and of the path substantially coincide. My prior application further teaches that such a curved panel may be pro- .vided with a deflection plate for impingement by the air stream to create a force tending to retract the panel.

It is apparent from the foregoing that a curved aileron mounted to move in a curved path may be designed with either an inherent tendency to the wing. These effects cause a rolling move- One of the objects of the present invention is to' move outward or an inherent tendency to retract. It is further apparent that the inherent tendency to retract may be derived from the above-mentioned eccentricity of curvature and/orzfrom a deflector plate carried by the aileron. Usually the end to be sought is an aileron that willmove readily and yet tend to retract to a degree readily perceptible to the pilot. If the tendency toretract varies with the extension of'the aileron, the varying resistance to movement of the control stick gives the pilot a feel of the control mechanism that is necessary for skillful flying. Various pilots, however, require different magnitudes of this retraction .force to feel at home at the controls, and, since multitudinous mental burdens are imposed on a pilot, it is important to satisfy individual preferences in this respect.

provide an aileron of the type under discussion that may be readily adjusted to suit the preferences of different pilots as to the magnitude of the force exerted by the aileron on the control mechanism in the cockpit. In the preferred practice of my invention the adjustability is afforded by a deflecting means adjustably carried by the aileron, the deflecting means being posistreamwhen ent extended position ofthe aileron. This difficulty is generally attributable to the fact that the angle' at whicha defl ting surface fixed on the curved'aileron meets e air stream varies with the degree to which the aileron is extended along its curved path. A further object sought in some practices of the present invention is to provide for the automatic adjustment of such a forcecontrolling member relative to the aileron in response to movement of the aileron along its path of extension and retraction. It is contemplated that the retraction tendency of; the aileron afforded by the deflecting means may be either increased or decreased automatically as the aileron is extended,'the variation in magnitude being in accord with whatever desired effect the designer has in mind.

As disclosed in myabove-mentioned copending application, I may find it to be desirable to provide one or more air passages through an aileron of the present type to prevent lag in responsive- -ness of the aircraft to aileron movement, such a passage or passages through the aileron being esfcating how the aileron may be equipped with ah air-deflecting member in combination with means for adjusting the deflecting member to selected flxed positions;

Fig. 7 is a fragmentary view of the aileron taken ing edge of the wing. The upper skin I3 of the pecially desirable if the aileron is positioned with in the forward 80% of the wing chord. Certain objects of the present invention relate to such an air passage. One of these objects is to cause the air passage through the aileron to-become effective early in the initial extension of the aileron.

This object is achieved by placing the passage through the aileron relatively close to the initially extended portionof the aileron and may be further favored by makingthe outer edge of the passage relatively sharp. Anotherof these objects is to provide a second function for the air stream through such an aileron passage, namely, the

function of applying pressure against an air-deflecting member, the air-deflecting member being mounted on the aileron at an angle to produce a desirable tendency for the aileron to move either inwardly or outwardly along its path of extension and retraction. The preferred form of my in vention is characterized by'a transverse slot in which is mounted a vane adapted to be moved to various positions for deflecting air flowing through the slot.

The above and other objects of my invention will be apparent in my'detailed description to follow, taken with the accompanying drawings.

In the drawings, which are to be considered as illustrative only:

Fig. 1 is a. diagrammatic plan view of an aileron in retracted position and the associated control mechanism, the aileron being equipped with an air-deflecting member that is automatically adjusted in response to movement of the aileron;

, Fig. 2 is a transverse section on an enlarged scale taken as indicated by the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 2 showing the aileron "in extended position;

Fig. 4 is a greatly enlarged section taken as indicated by the irregular line 44 of Fig. 2; a

Fig. 5 is an enlarged section taken as indicated by the line 5-5 of Fig. 3; a

Fig. 6 is an enlarged fragmentary section indiwing =|2 is formed with an .opening' l5 through which the aileron is extended and retracted, and the lower skin I8 .ofthe wing may have one or more openings l1 throughwhich air may enter and subsequently flow outward through the upper opening I 5 as indicated'by arrows in Fig. 3.

In the particular construction shown in the drawings, an aileron panel l8includes a plate 2| of suitable material that is bent to form a forward curved wall or skin 22, a rearward curved wall or skin 23, and an inner endwall 25. The plate 2| is attached by its opposite side edges to the corresponding track members He, the track members including webs 26 that serve as side walls for the-panel. The track we bs 26 are of flaring configuration towards their outer endsqand are interconnected at their outer ends by a plate 21 that serves as the outer end wall of the panel.

The end plate 21 is spaced from the two edges of the plate 2| to form 'a passage or slot '28 that permits air to flow rearward through the panel. In the particular construction shown in the drawings, a wall for the passage 28 is provided by a channel member 30 mounted :between the edges of the plate 2|, and a second wall for the passage is provided by an angular plate 3| attached to the inner side of the end plate 21. It will be noticed that the passage 28 is at the outer end of the aileron to .become effective whenever outward extension of the aileron is initiated and that the passage 28 has a relatively sharp forward edge 32 provided by the end plate 21.

Each of the curved track members 20 provides a. laterally extending curved flange 33 extend-- ing adjacent one of the ribs 35 of the wing. In-

vided with an anti-friction bearing 43 and is re-' tained on its spindle 3-1 by a suitable nut 15. Four such guide rollers 38- mounted on spindles 31 may be provided, two rollers eng n the upper side of the track flange 33 and two of the assaioa rollers en a in the lower side of the track flange, the fo'urrollers :being disposed, for example, as best shown in Fig. 3. The track flange 33 may have integral stop portions 45 at its inner end to cooperatewith the rollers 33 to limit the outward movement of the aileron panel.

e If the aileron I is of such length that it must be divided into more than one panel Hi to clear ribs 35 in the wing l2, the various panelsmay have a common end plate 21-, "the end plateserving to interconnect the panels in a unitary man- It is apparent that the end plate 21 may have several functions and purposes. In addition to the functions and purposes already mentioned, the end plate 21 serves as a closure for the wing opening l when the aileron I0 is retracted and serves as what may be termed a primary deflection. plate when the aileron is extended as shown in Fig. 3. In deflecting the air stream when the aileron is extended, the end. plate 21 creates by reaction to the airstream a tendency for the aileron to retract into the wing.

It is to be noted that in designing the aileron ill for an inherent tendency to retract into an airplane wing, reliance may be placed on such a primary deflecting means in the form of the end plate 21, or reliance may be placed on eccentricity of curvature of the aileron relative to the curvature of the aileron path as determined by the configuration of the track flange 33. If such eccentricity exists, the forward skin 22 of the aileron serves as the primary deflecting means, since the eccentricity is effective by reason of the air stream impinging against and being, de-

flected-by' the forward side of the aileron. In some practices of my invention reliance may be placed on both of these expedients.

In the'particular form of the invention shown in Figs. 1 to 5, it may be. assumed that both the curvature of the aileron as represented by the forward skin 22 and the curvature of the path of the aileron as represented by the track flange 33 have alcommon center or axis of curvature designated 41 in Fig. 3. In such an arrangement the air stream impingingon the forward skin 22 of the aileron has substantially no effect on the aileron with respect to movement along its curved path, and the tendency of the aileron to retract is derived primarily from air pressure exerted against the inclined surface'of the end or deflecting plate 21.

The aileron l0 may be actuated by any suitable control mechanism. In. the particular construction shown in Figs. 1 to 5 a suitable operating'shaft 50 extends through each wing l2, the operating shaft being joumaled in suitable bearings 5| and comprising a number of shaft sections 52 interconnected by suitable couplings 53.

61 wound on the drum 56 pass around various pulleys 68 and around drums 10 on the inner ends of the shafts 50. When the control stick 55 is swung to the left, as viewed in Fig. 1 for 1 example, the leftaileron i0 is extended to cause the left wing [2 to drop and simultaneously cause the drag in the left wing, to increase.

The form of the invention shown in Figs. 1 to 5 is characterized by deflecting means having the function of automatically varying automatically modifying the inherent tendency of the aileron to retract in response to pressure from the air stream. it In the absence of the end plate 21, such an automatic means in a concentric arrangement would be the sole factor. determining the tendency of the aileron to retract. In the presence of the end plate 21,

however, the automatic deflecting means serves as an auxiliary deflecting means to supplement the actuating effect of the-end plate, and the effect of the auxiliary deflecting means may be either to oppose or to augment force created by. ,theprimary deflecting means or end'plate Since it is necessary merely that the auxiliary deflecting means be subject to the pressure of the air stream to serve its purpose, it is apparent that the auxiliary\ deflecting means may be mounted at various locations on the aileron III. A feature of the preferred form oi. the

invention, however, is the concept'of mountin the auxiliary deflecting means within the confines of the air passage or slot 28.

As best shown in Figs. 2, 3, and 5,. a hollow vane 12 of streamline configuration may be unit'ary with two end discs 13 providing trunnions 15. An anti-friction bearing 15 journaling each of the trunnions 15 is housed in a suitable fitting '11 and each of the two fittings is mountedon the inner face of the corresponding track mem ber 20 by suitable screws-18. The described arrangement permits the vane or deflecting mem--, ber 12 to rotate freely on the axis defined by the twotrlmnions 15.

Any suitable actuating means may be provided to cause the vane 12 to berotated automatically omits axis in the'course of movement of the aileron l0 along its curved For example,the

desired control of the vane may be achieved by a suitable operating connection'with the mecha-' nism for actuating the aileron. Thus I. may

For each aileron panel 18 in a wing the operating shaft 50 is provided with a pair of spaced actuating arms-generally designated 55, each acand the adjustable links are in tum connected to the aileron panel by pivot means G0. The

' pivot means 50 at the end of each adjustable link 58 may be mounted in a pair of, bracket plates 6| unitary with the aileron panel.

It is apparent that rotation of. one of the operating shafts '50 causes corresponding extension or retraction of-the corresponding aileron;

it along its curved path as may be readily. un-

derstood by comparing Figs. 2 and'3. Any of the.

various well known arrangements may be emsimply connect the vane 12 to the previously mentiqied pivot 51 by a suitable link 80. .As indicated inFig. 1 there may be two such links 55, one for each ofthetwo pivot means 51, and as shown in Figs. 3 and 5 each of the links 30 may be pivotally connected to a suitable stud ll 1 corresponding disc 13 at one end mounted on the of the vane. Y

Comparison of Figs. land 3 reveals that each oi the pivot means 51 in the mechanism for controlling the aileron is relatively close, to the rotary axis of the vane 12 when the aileron is retracted, but the intervening-distance progressively increases as the aileron is extended. Since this distance progressively changes, the link II the, vane to rotate in accord with movement of the'aileron along the curvedaiieron ltwillbereadllyapparenttothoseskilledin ends inlthe automatic operation of the vane I2.

In the arrangement shown in Figs. 1 to 5, for example, the vane may be intended to modify the inherent tendency of the aileron toretract whoa; extended into the air stream, As stated heretofore, the inherent tendency of this particular aileron to retract in the absence oi'a vane I2 is derived solely from the effect of the end plate or deflection plate 21, since the curvature of the aileron and the curvature of'the aileron path are concentric. The desirability of modifying the inherent tendency of the aileron to retract may arise from the fact that the deflection plate 21 on "the end of the aileron moves into relatively steep angles as the aileron approaches its upper limit arrangement, however, the vane 12 is automatically rotated into angles to progressively oppose retraction of the ailerhn as the aileron approaches its upper limit position. In other words, the air.

stream passing through the aileron slot 28 im--' a pingeson the inclined forward or under face of the vane, thereby creating a minor force tending to extend the aileron, and this minor force modifies or opposes the major force in the opposite direction caused by the deflection plate 21. It is apparent that the vane may likewise be arranged to modify or supplement inherent aileron forces produced by eccentricity between the curvature of tthe aileron and the curvature of the aileron Figs. 6 and '1 indicate how an adjustable vane 82 similar in configuration to the automatic vane 12 may be mounted in the same position in the aileron slot 28. The vane 82 is attached at each being rotatably mounted on the aileron by trunnions' 88 in the manner heretofore described with reference to the end discs 13. Each of the worm. ears 83- at each end of the aileronslot 28 is in mesh with an adjustment worm having an end slot 81. At ,its forward end each adjustment worm 88 is joumaled in a suitable bore 88 in the aileron. structure and is provided with a head 88 to prevent axial movement, while the rear end of the worm extends through a second bore Si in the aileron structure and is provihd with a pain of lock nuts 92. For reinforcementgof the aileronstructure in the vicinity of each worm 88 a U- p d strap 82 may be employed at each end of the aileron slot 28 as shown in Fig. 8.

- The vane 82* has substantially no force-creating eii'ect with respect to the aileron if idle vane v is tangential to the center or axis of curvature of the ailemn path, 1. e. it the-vane is' perpendicular to a radius drawn to thecenter of'curvature of the track flange 8,2. Atsuch a position of adiustment. which may be termed the neutral position. as indicatui by the dotted 1196 u him-"3,

impingement or the air clainst the inclined imder' surface ofthe vane will create a force. tending to extend the aileron. :On the ethahand. if the vane 82 is inclined downwardly to the-position indicated by the dotted line II, the

impinging on the inclined upperair;

face or the'vane will create a force tending to retract the aileron. In either inclined position corresponding numerals. .The aileron I88 diflers from the first described construction, first, inthe omission of a vane in the slot I8I'and, second, in the fact that the aileron has an end plate or deflecting member I82 that is movable to various angles relative to the aileron.

In the particular construction shown in- Figs. 8 and 9 the end plate I82, suitably reinforced by an angular plate I83, is pivoted on studs I85 at each end of the slot I8I. Also at each end of the slot I8l a'bell-crank I88 mounted on a suitable pivot means I81 has one arm connected to the previously mentioned operating rod 88 and has its other arm connected by a link I88 to a small arm matically causes the end plate I82 to rotate clockwise through a substantial angle. The purpose of providing such clockwise rotation of the end plate is in this instance to avoid any excessive tendency of air impinging on the end plate-to cause theafleron to retract from the position in a Fig. 9. Obviously the arrangement may be'adapted to increase rather than decrease the tendency end to a worm gear 83, the two worm gears 88 I of the aileron to retract.

The aileron II: shown in Fig. 10 issimilar to the last-described aileron shown in Figs. 8 and 9, corresponding numerals being employed to designate corresponding parts; The-aileron of Fig. 10 .difiers, however, in the omission of the spanwise slot or passage MI. The upper or forward wall H3 of this aileron is solid except for small foreand-aft. slots II: through which the bell-cranks we extend.

and changed radically in embodying my basic concepts, and I reserve the right therefore to all expressions of the invention that properly lie within the scope of my appended claims.

I claim as my invention: v r l. In an aircraft, the combination of: anairfoil having a hollow portion with an opening to the surface of the airfoil; an aerodynamic member mounted in said hollow portion, said aerodynamic member being movablealong a path through said opening into the air stream outside .65 the airfoil; actuating means to move said aerodynamic member along said path; means movably mounted on said aerodynamic member to present a deflection surface to the air stream thereby to create a force tending to move the aerodynamic member along said path; and means to move said deflection means relative to said aer dynamic member in accord with changes in poittion of the aerodynamic member along said pa 7 6 2. man aircraft, the combination of: an airthe vane 82 willmodify the inherent tendency of I I8 integral with the end plate I82. As the aileron I88 is shifted outward to its 'extreme position indicated in Fig. 9, the described mechanism auto- It will be readily understood that the specific arrangements described herein 'may be modified foil having a hollow portion with an opening to the surface of the airfoil; an aerodynamic member'mounted in said hollow portion to move on a path, through said opening into the air stream outside the airfoil, said aerodynamic member having an inherent tendency to move along said path,

said aerodynamic member having a passage there- .through to permit flow of air from one side of the aerodynamic member to the other when the member is extended into the air stream; means movably mounted on said aerodynamic member topresent a deflecting surface V to said air flowing through said passage thereby to create a force to modify said tendency of the aerodynamic member to move along said path; and means to vary the position of said deflecting meansrelative to said aerodynamic member in response to movement of the aerodynamic member along said path.

3. In an aircraft, the combination of an airfoil having a hollow portion with an, opening to the surface of the airfoil; an aerodynamic member of curved fore-and-aft cross-sectional configuration mounted in said hollow portion to extend through ber'to m e along said path, said auxiliary meansbeing movable through a range of angles relative to the aerodynamic member to vary the magnitude of said supplemental tendency; andmeans to vary the position of said auxiliary deflecting means relative to said aerodynamic member in response to movement of the aerodynamic member along said pa h.

4. In an aircra t, the combination of: an airfoil having a. hollow portion with an opening to the surface of the airfoil; an aerodynamic member mounted in said hollow portion toextend through said opening, said aerodynamic member having a-transverse slot therethrough to permit flowof air from one side of the aerodynamic member to the other when the aerodynamic member is in an extended position, said slot.

being close to the outer end of said aerodynamic member to. cause early initiation. of air flow through the slot when the aerodynamic member is initially extended; means to shift said aerodynamic member on a path through said opening into an air stream outside the airfoil; and a vane mounted across said slot lengthwise thereof at an angle to deflect air flowing through the slot thereby to create a force tending '.to move the aerodynamic member along said path.

5. In an aircraft, the combination of: an air foil having a hollow portion with an opening to the surface of the airfoil; an aerodynamic mem-- ber mounted in said hollow portion to extend through said opening, said aerodynamic member having a transverse slot to permit flow of air through said aerodynamic member from one side to the other when said aerodynamic member is extended through said opening; means to shift said aerodynamic member on a path through said opening; and deflection means mounted in said slot for rotational adjustment about an axis lengthwise of the slot, said deflection means being narrower than the slot, whereby the deflection means may be rotated to restrict but not .cut off air flow through the slot.

'6. In an aircraft, the combination of: an airfoil having a hollow portion with an opening to the surface of the airfoil; an aerodynamic member mounted in said hollow portion, said aerodynamic member being movable along a path through said operfing into the airstream outside the airfoil; deflection means movably mounted on said aerodynamic member to present a deflection surface to the airstream, whereby aforce is exerted upon the aerodynamic member in the direction of its travel; and actuating means associated with said deflection means, said actuating means being operative by movement of said aerodynamic member along such path, whereby the resultant force of the air stream on said member in the direction of its travel is maintained at the'desired value at every portion of such travel.

7. In an aircraft, the combination of: an air- I foil a hollow portion with an opening to the surface of the airfoil; an aerodynamic member mounted in said hollow portion to extend through said opening, said aerodynamic member having a transverse slot to permit flow of air through said aerodynamic member from one side to the other when said aerodynamic member is in an extended position; means to shift said aerodynamic member on a path through said opening; and deflection means mounted in said slot for rotational adjustment about an axis lengthwise of the slot, said slot being near the outer end of the aerodynamic member and the outer edge of said slot being relatively sharp to permit early initiation of air flow through the slot when the aerodynamic member is initially extended along said path.

' EDWARD F. ZAP.

CERTIFIHCATE OF CORRECTION.

Patent No. 2,383,332. j August 21, 19%..

ZAP.

It is hereby' eertii'ied that error appears in the printed spec-iiication of the above m'zmbered patent requiring correction as follows: Page 5, secand column, line 16, after "varying" insert --or--; and that the said Letters Pate t should be read-with this correction therein that the same 'may conform to the record of the ease in the Patent Office. I

Si'gzied end seaied this 14th day of December, A. D. 19145 a Leslie Frazer (Seal) First Assistant Comnissioner of Patents. 

